Good question..I think it’s cuz it would look out of place? We are so used to not seeing it and if they were to start drawing them in now it would look awkward..
Another reason could be that technically if u think abt it these stories are kinda from their perspective so I guess u can think of it being like they only see the other person as this most beautiful person that’s perfect for them? Maybe idk
I wonder sometimes, why don't they show double chins??? Like, skinny people have double chins if you press, so why don't they have one, or she least show one???